re2c has ext submodule, don't fail fataly w/ local sources

If we need to use some source other than github.com for our bext
repositories, historically the user had to manually set up the
remappings to make that work.

This commit adds support for a BEXT_REPOSITORY_ROOT CMake variable that
will handle the necessary redirects automatically.

.github/workflows/binary_dependencies.yml

@@ -132,7 +132,7 @@ jobs:
 
   macos_release:
     name: macOS Clang Release Build
-    runs-on: macos-14
+    runs-on: macos-15
     outputs:
       artifact-id: ${{ steps.upload.outputs.artifact-id }}
     steps:
@@ -158,7 +158,7 @@ jobs:
         if: github.ref == 'refs/heads/main'
         shell: bash
         env:
-          BEXT_CHANNEL: macos-14-${{ runner.arch }}-release
+          BEXT_CHANNEL: macos-15-${{ runner.arch }}-release
         working-directory: ${{ runner.temp }}/bext_output
         run: |
           test -d install
@@ -171,8 +171,8 @@ jobs:
         id: upload
         uses: actions/upload-artifact@v4
         with:
-          name: bext-macos-14-${{ runner.arch }}-release-${{ github.sha }}
-          path: ${{ runner.temp }}/bext-macos-14-${{ runner.arch }}-release.tar.gz
+          name: bext-macos-15-${{ runner.arch }}-release-${{ github.sha }}
+          path: ${{ runner.temp }}/bext-macos-15-${{ runner.arch }}-release.tar.gz
           if-no-files-found: error
           retention-days: ${{ env.BEXT_ARCHIVE_RETENTION_DAYS }}
           compression-level: 0
@@ -205,7 +205,7 @@ jobs:
           CURRENT_ARTIFACT_IDS: ${{ needs.linux_release.outputs.artifact-id }},${{ needs.windows_ninja_release.outputs.artifact-id }},${{ needs.macos_release.outputs.artifact-id }},${{ steps.marker.outputs.artifact-id }}
         run: |
           set -euo pipefail
-          artifact_pattern='^bext-((ubuntu-24\.04|windows-2025|macos-14)-(X86|X64|ARM|ARM64)-release|production)-'
+          artifact_pattern='^bext-((ubuntu-24\.04|windows-2025|macos-15)-(X86|X64|ARM|ARM64)-release|production)-'
           artifact_rows="$(gh api --paginate "repos/$GITHUB_REPOSITORY/actions/artifacts?per_page=100" --jq '.artifacts[] | [.id, .name] | @tsv')"
           while IFS=$'\t' read -r artifact_id artifact_name; do
             if [[ "$artifact_name" =~ $artifact_pattern && ",${CURRENT_ARTIFACT_IDS}," != *",${artifact_id},"* ]]; then

.gitmodules

@@ -126,6 +126,7 @@
 [submodule "itk/itk"]
 	path = itk/itk
 	url = https://github.com/BRL-CAD/itk
+	branch = main
 	ignore = dirty
         shallow = true
 [submodule "iwidgets/iwidgets"]

CMake/BextBootstrap.cmake

@@ -1,6 +1,8 @@
 set(bext_root "${CMAKE_CURRENT_LIST_DIR}/..")
 get_filename_component(bext_root "${bext_root}" ABSOLUTE)
 
+include("${CMAKE_CURRENT_LIST_DIR}/BextGit.cmake")
+
 if (NOT DEFINED PROFILE)
   message(FATAL_ERROR "Set PROFILE to one of: auto, bundled, minimal, everything")
 endif (NOT DEFINED PROFILE)
@@ -73,19 +75,6 @@ if (LIST_ONLY)
   return()
 endif (LIST_ONLY)
 
-set(git_args submodule update --init --recursive --jobs 8)
-if (GIT_SHALLOW_CLONE)
-  list(APPEND git_args --recommend-shallow)
-endif (GIT_SHALLOW_CLONE)
-list(APPEND git_args -- ${project_paths})
-if (WIN32)
-  list(PREPEND git_args -c core.longpaths=true)
-endif (WIN32)
-
-execute_process(
-  COMMAND ${GIT_EXECUTABLE} ${git_args}
-  WORKING_DIRECTORY ${bext_root}
-  COMMAND_ERROR_IS_FATAL ANY
-)
+bext_git_submodule_update("${bext_root}" --jobs 8 -- ${project_paths})
 
 message(STATUS "Bootstrap complete for profile ${profile}")

CMake/BextGit.cmake

@@ -0,0 +1,104 @@
+# Shared repository selection for configure-time and bootstrap submodule updates.
+# Keep .gitmodules canonical and scope all overrides to the Git process tree.
+include_guard(GLOBAL)
+
+set(_BEXT_GIT_CANONICAL_ROOT "https://github.com/BRL-CAD")
+set(BEXT_REPOSITORY_ROOT "${_BEXT_GIT_CANONICAL_ROOT}" CACHE STRING
+  "Repository URL or local mirror directory containing bext's dependency repositories")
+
+function(bext_git_repository_root out_root out_local)
+  set(root "${BEXT_REPOSITORY_ROOT}")
+  set(local FALSE)
+  if (root STREQUAL "")
+    message(FATAL_ERROR "BEXT_REPOSITORY_ROOT must be a repository URL or local mirror directory")
+  endif ()
+
+  # Check drive paths before URL schemes or scp-style SSH locations.
+  if (root MATCHES "^file://")
+    set(local TRUE)
+    string(REPLACE "=" "%3D" root "${root}")
+  elseif (root MATCHES "^[A-Za-z]:[/\\\\]" OR
+      NOT (root MATCHES "^[A-Za-z][A-Za-z0-9+.-]*://" OR root MATCHES "^[^/]+:.+"))
+    set(local TRUE)
+    string(REPLACE "\\" "/" root "${root}")
+    if (WIN32 OR NOT root MATCHES "^[A-Za-z]:/")
+      get_filename_component(root "${root}" ABSOLUTE
+        BASE_DIR "${CMAKE_CURRENT_FUNCTION_LIST_DIR}/..")
+    endif ()
+    # Encode path characters with special meaning in a file URL.  In
+    # particular, a literal % in a native path must not become a URL escape.
+    string(REPLACE "%" "%25" root "${root}")
+    string(REPLACE " " "%20" root "${root}")
+    string(REPLACE "#" "%23" root "${root}")
+    string(REPLACE "?" "%3F" root "${root}")
+    string(REPLACE "=" "%3D" root "${root}")
+    if (root MATCHES "^[A-Za-z]:/")
+      set(root "file:///${root}")
+    elseif (root MATCHES "^//")
+      set(root "file:${root}")
+    else ()
+      set(root "file://${root}")
+    endif ()
+  endif ()
+
+  if (NOT root MATCHES "^file:///*$")
+    string(REGEX REPLACE "/+$" "" root "${root}")
+    string(APPEND root "/")
+  else ()
+    set(root "file:///")
+  endif ()
+  set(${out_root} "${root}" PARENT_SCOPE)
+  set(${out_local} "${local}" PARENT_SCOPE)
+endfunction()
+
+function(bext_git_submodule_update working_directory)
+  find_program(GIT_EXECUTABLE git)
+  if (NOT GIT_EXECUTABLE)
+    message(FATAL_ERROR "Need to populate Git submodules, but unable to find git executable")
+  endif ()
+
+  bext_git_repository_root(root local)
+  set(git_command "${GIT_EXECUTABLE}")
+  if (WIN32)
+    list(APPEND git_command -c core.longpaths=true)
+  endif ()
+  if (NOT root STREQUAL "${_BEXT_GIT_CANONICAL_ROOT}/")
+    list(APPEND git_command -c "url.${root}.insteadOf=${_BEXT_GIT_CANONICAL_ROOT}/")
+  endif ()
+
+  set(shallow_args)
+  if (local)
+    list(APPEND git_command -c protocol.file.allow=always)
+    # The environment restriction also reaches recursive Git processes and
+    # overrides any protocol permissions in the user's Git configuration.
+    list(PREPEND git_command "${CMAKE_COMMAND}" -E env GIT_ALLOW_PROTOCOL=file --)
+    list(APPEND shallow_args --no-recommend-shallow)
+  elseif (GIT_SHALLOW_CLONE)
+    list(APPEND shallow_args --recommend-shallow)
+  endif ()
+
+  execute_process(
+    COMMAND ${git_command} submodule update --init --recursive ${shallow_args} ${ARGN}
+    WORKING_DIRECTORY "${working_directory}"
+    RESULT_VARIABLE git_result
+  )
+  if (NOT git_result STREQUAL "0")
+    set(local_note "")
+    if (local)
+      set(local_note " Only file transport is permitted; all required repositories and pinned commits must be available locally, including recursive submodules.")
+    endif ()
+    message(WARNING
+      "Git submodule update failed in ${working_directory} using BEXT_REPOSITORY_ROOT=${BEXT_REPOSITORY_ROOT} (${git_result}).${local_note}")
+  endif ()
+endfunction()
+
+bext_git_repository_root(_bext_git_root _bext_git_local)
+message(STATUS "bext repository root: ${_bext_git_root}")
+if (_bext_git_local)
+  message(STATUS "bext Git updates: file transport only, shallow recommendations disabled")
+  if (GIT_SHALLOW_CLONE)
+    message(STATUS "Ignoring GIT_SHALLOW_CLONE for the local repository mirror")
+  endif ()
+endif ()
+unset(_bext_git_root)
+unset(_bext_git_local)

CMake/Utils.cmake

@@ -34,6 +34,7 @@
 #
 ###
 
+include("${CMAKE_CURRENT_LIST_DIR}/BextGit.cmake")
 
 ###############################################################################
 # It is common for more complex targets to need to key build settings off of
@@ -102,23 +103,8 @@ endmacro(TargetInstallDeps root)
 function(git_submodule_init path checkfile)
   string(REGEX REPLACE "[^A-Za-z0-9_+.-]" "_" stamp_name "${path}")
   set(sha1_stamp "${CMAKE_CURRENT_BINARY_DIR}/build_sha1_${stamp_name}.txt")
-  if (NOT EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${path}/${checkfile})
-    find_program(GIT_EXECUTABLE git)
-    if (NOT GIT_EXECUTABLE)
-      message(FATAL_ERROR "Need to populate Git submodule, but unable to find git executable")
-    endif (NOT GIT_EXECUTABLE)
-    set(git_args submodule update --init --recursive)
-    if (GIT_SHALLOW_CLONE)
-      list(APPEND git_args --recommend-shallow)
-    endif (GIT_SHALLOW_CLONE)
-    if (WIN32)
-      list(PREPEND git_args -c core.longpaths=true)
-    endif (WIN32)
-    execute_process(
-      COMMAND ${GIT_EXECUTABLE} ${git_args} ${path}
-      WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
-      COMMAND_ERROR_IS_FATAL ANY
-    )
+  if (NOT EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/${path}/${checkfile}")
+    bext_git_submodule_update("${CMAKE_CURRENT_SOURCE_DIR}" -- "${path}")
     if (NOT EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/${path}/${checkfile}")
       message(FATAL_ERROR "Git submodule ${path} is missing ${checkfile} after checkout")
     endif ()
@@ -129,7 +115,7 @@ function(git_submodule_init path checkfile)
       OUTPUT_STRIP_TRAILING_WHITESPACE
     )
     file(WRITE "${sha1_stamp}" ${GIT_SHA1})
-  else (NOT EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${path}/${checkfile})
+  else ()
     execute_process(
       COMMAND git log -1 --format=%H
       WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/${path}
@@ -148,7 +134,7 @@ function(git_submodule_init path checkfile)
       endif (NOT "${BUILD_SHA1}" MATCHES "${GIT_SHA1}")
     endif()
     file(WRITE "${sha1_stamp}" ${GIT_SHA1})
-  endif (NOT EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${path}/${checkfile})
+  endif ()
 endfunction(git_submodule_init path)
 
 ###############################################################################

INSTALL.md

@@ -50,6 +50,58 @@ Shallow clone options:
 Shallow clones are fine for compile-only use, but they are not recommended for
 development or for submodule update work.
 
+# Alternate repositories and offline mirrors
+
+`BEXT_REPOSITORY_ROOT` selects the directory containing the dependency
+repositories.  It defaults to `https://github.com/BRL-CAD`.  For another host,
+specify the URL of the equivalent repository directory:
+
+```sh
+cmake --preset auto -DBEXT_REPOSITORY_ROOT=https://git.example.org/brlcad
+```
+
+For offline use, the directory can contain bare Git mirrors such as
+`bext.git`, `astyle.git`, and `libpng.git`, as produced by BRL-CAD's
+`sh/mirror_repos.sh`.  Clone bext first, then let CMake populate the required
+submodules:
+
+```sh
+git clone /path/to/mirror/BRL-CAD/bext.git
+cd bext
+cmake --preset auto -DBEXT_REPOSITORY_ROOT=/path/to/mirror/BRL-CAD
+```
+
+The root points directly to the repositories; CMake does not append `BRL-CAD`.
+Local paths and `file://` URLs are supported, as are remote Git URLs including
+`ssh://` URLs.  Relative local paths are resolved against the bext source
+directory.  Quote the `-D` argument if the path contains spaces.  The setting
+is saved in the configure cache.
+
+The optional bootstrap script accepts the same setting:
+
+```sh
+cmake -DPROFILE=auto -DBEXT_REPOSITORY_ROOT=/path/to/mirror/BRL-CAD \
+  -P CMake/BextBootstrap.cmake
+```
+
+Bootstrap runs separately from configure, so pass the setting to both commands
+if you use both workflows.  `LIST_ONLY=ON` previews bootstrap selection without
+fetching.
+
+CMake redirects `https://github.com/BRL-CAD/` URLs using command-scoped Git
+configuration, including recursive submodule operations.  Local roots enable
+file transport and forbid network transport for those Git operations.  They
+also disable shallow-clone recommendations, even with `GIT_SHALLOW_CLONE=ON`,
+so full mirrors can supply older pinned commits.  The mirrors must contain all
+required commits.  Recursive submodules outside that URL prefix need their
+own Git URL mappings and local mirrors; otherwise initialization fails.
+
+The override does not change `.gitmodules` or install persistent Git rewrite
+settings.  To return CMake-driven updates to GitHub, set
+`-DBEXT_REPOSITORY_ROOT=https://github.com/BRL-CAD`.  Direct Git commands use
+their normal configuration.  This setting controls submodule fetching, not
+network access by dependency build scripts.
+
 # Path and directory caveats
 
 * Avoid symlinked source or build directory paths.  `bext` warns about these

README.md

@@ -34,6 +34,10 @@ cmake --preset auto
 Use `LIST_ONLY=ON` to preview the selected submodules without fetching them,
 and `GIT_SHALLOW_CLONE=ON` to specify shallow clones during bootstrap.
 
+Both configure and bootstrap accept `BEXT_REPOSITORY_ROOT` to fetch from an
+alternate host or a local Git mirror.  See [alternate repositories and offline
+mirrors](INSTALL.md#alternate-repositories-and-offline-mirrors) for examples.
+
 # How manual selection works
 
 Build selection happens in three layers:
@@ -61,49 +65,6 @@ When `bext` is driven from a BRL-CAD build, `BRLCAD_COMPONENTS` can further
 narrow some BRL-CAD-related packages to only those needed by the requested
 component set.
 
-## Xmin-backed bundled toolkits
-
-An installed Xmin SDK can provide the X11 and OpenGL surface for bext's
-bundled Tk and Qt.  Set `BEXT_XMIN_ROOT` to select the standard Xmin profile:
-
-```sh
-cmake -S /path/to/bext -B /path/to/bext-build \
-  -DBEXT_XMIN_ROOT=/absolute/path/to/xmin-sdk \
-  -DENABLE_TCL=ON -DENABLE_QT=ON
-```
-
-The profile affects only Tk and Qt packages selected for a local build.  It
-does not enable a package excluded by `USE_*`, `BRLCAD_COMPONENTS`, or an
-explicit `DISABLE_*` setting.
-
-* Tk is configured with `--with-xmin` and bext's matching Tk patch.
-* Qt is built with the matching Xmin patch, the qxcb desktop-OpenGL profile,
-  and dependency audits that reject accidental host X11 or OpenGL linkage.
-
-The patches are maintained next to the dependency build logic as
-`tk/tk_xmin.patch` and `qt/qt_xmin.patch`.  They are tied to the exact Tk
-and Qt submodule revisions in this repository.  Updating either dependency
-therefore requires updating its patch; a stale patch fails during the patch
-step rather than silently producing a mixed build.
-
-The Xmin SDK must include toolkit-client support for Tk.  Qt additionally
-requires the Qt X11 compatibility client and client OpenGL support.  Normal
-system discovery is unchanged when `BEXT_XMIN_ROOT` is empty.
-
-Qt's installed package metadata retains an explicit dependency on Xmin.
-Downstream projects must therefore keep the same SDK discoverable with
-`Xmin_DIR` or `CMAKE_PREFIX_PATH`; configuration fails instead of falling back
-to host X libraries when that SDK is absent.
-
-## Advanced toolkit patch controls
-
-Unix builds may pass additional, semicolon-separated absolute patch paths in
-`TK_EXTRA_PATCHES`, plus additional Tk `configure` arguments in
-`TK_CONFIGURE_ARGS`.  `QT_EXTRA_PATCHES` provides the corresponding Qt
-hook.  `QT_XMIN_ROOT` remains available for manually supplied Qt Xmin patches.
-These low-level controls are not needed when `BEXT_XMIN_ROOT` selects the
-standard profile.
-
 # Official profiles
 
 The supported configure entry points are:
@@ -219,3 +180,4 @@ cmake ../brlcad \
 * [DEPENDENCIES.md](DEPENDENCIES.md) - package-to-group reference, output
   classification, and dependency addition workflow
 * [NOTES.md](NOTES.md) - maintainer notes and submodule procedures
+* [XMIN.md](XMIN.md) - testing-only headless X11 support using Xmin

XMIN.md

@@ -0,0 +1,48 @@
+# Xmin-backed bundled toolkits
+
+Xmin is a small, self-contained X11 server and client library - see
+https://github.com/starseeker/Xmin
+
+An installed Xmin SDK can provide the X11 and OpenGL surface for bext's
+bundled Tk and Qt, allowing fully interactive automated GUI application testing
+in an environment that has neither X nor OpenGL.
+
+Set `BEXT_XMIN_ROOT` to select the standard Xmin profile:
+
+```sh
+cmake -S /path/to/bext -B /path/to/bext-build \
+  -DBEXT_XMIN_ROOT=/absolute/path/to/xmin-sdk \
+  -DENABLE_TCL=ON -DENABLE_QT=ON
+```
+
+The profile affects only Tk and Qt packages selected for a local build.  It
+does not enable a package excluded by `USE_*`, `BRLCAD_COMPONENTS`, or an
+explicit `DISABLE_*` setting.
+
+* Tk is configured with `--with-xmin` and bext's matching Tk patch.
+* Qt is built with the matching Xmin patch, the qxcb desktop-OpenGL profile,
+  and dependency audits that reject accidental host X11 or OpenGL linkage.
+
+The patches are maintained next to the dependency build logic as
+`tk/tk_xmin.patch` and `qt/qt_xmin.patch`.  They are tied to the exact Tk
+and Qt submodule revisions in this repository.  Updating either dependency
+therefore requires updating its patch; a stale patch fails during the patch
+step rather than silently producing a mixed build.
+
+The Xmin SDK must include toolkit-client support for Tk.  Qt additionally
+requires the Qt X11 compatibility client and client OpenGL support.  Normal
+system discovery is unchanged when `BEXT_XMIN_ROOT` is empty.
+
+Qt's installed package metadata retains an explicit dependency on Xmin.
+Downstream projects must therefore keep the same SDK discoverable with
+`Xmin_DIR` or `CMAKE_PREFIX_PATH`; configuration fails instead of falling back
+to host X libraries when that SDK is absent.
+
+## Advanced toolkit patch controls
+
+Unix builds may pass additional, semicolon-separated absolute patch paths in
+`TK_EXTRA_PATCHES`, plus additional Tk `configure` arguments in
+`TK_CONFIGURE_ARGS`.  `QT_EXTRA_PATCHES` provides the corresponding Qt
+hook.  `QT_XMIN_ROOT` remains available for manually supplied Qt Xmin patches.
+These low-level controls are not needed when `BEXT_XMIN_ROOT` selects the
+standard profile.

expat/CMakeLists.txt

@@ -3,7 +3,7 @@ bext_enable(EXPAT)
 
 if (ENABLE_EXPAT)
 
-  git_submodule_init(libexpat CMakeLists.txt)
+  git_submodule_init(libexpat expat/CMakeLists.txt)
 
   RegisterDeps(EXPAT)
 

iwidgets/README.bext

@@ -48,6 +48,13 @@ bwish and Archer where Tk was initialized first.  The patch uses the fully
 qualified ::iwidgets::Labeledwidget class name so both supported initialization
 orders behave identically.
 
+Panedwindow's frame hull shares its resource class name with Tk's native
+panedwindow widget, whose event bindings call a different widget API.  The
+patch removes that class tag from the hull's binding list while retaining
+Iwidgets' configure and sash bindings and the Panedwindow resource class.
+Pointer motion and clicks therefore use the correct handlers without
+changing native Tk panedwindow behavior.
+
 These changes are kept as a bext patch rather than modifications to the source
 submodule.  That keeps the imported upstream revision identifiable and makes
 the compatibility delta explicit and independently reviewable.  The external

iwidgets/iwidgets_itcl4.patch

@@ -223,6 +223,22 @@ index 032021e..4f94a4d 100755
  	    -relief sunken -borderwidth 2 -width 10
      }
  
+diff --git a/generic/panedwindow.itk b/generic/panedwindow.itk
+--- a/generic/panedwindow.itk
++++ b/generic/panedwindow.itk
+@@ -134,8 +134,11 @@
+     # Add binding for the configure event.
+     #
+     bind pw-config-$this <Configure> [itcl::code $this _pwConfigureEventHandler %w %h]
++    # Tk's native Panedwindow uses the same class name but a different API.
++    # Keep the hull's resource class and Iwidgets' own event bindings.
+     bindtags $itk_component(hull) \
+-	    [linsert [bindtags $itk_component(hull)] 0 pw-config-$this]
++	    [linsert [lsearch -all -inline -not -exact \
++		    [bindtags $itk_component(hull)] Panedwindow] 0 pw-config-$this]
+     
+     array set _relief {0 sunken 1 raised}
+ 
 diff --git a/generic/radiobox.itk b/generic/radiobox.itk
 index 282eaa7..fe1b11e 100755
 --- a/generic/radiobox.itk

oidn/CMakeLists.txt

@@ -7,6 +7,17 @@ if (ENABLE_OIDN)
 
   RegisterDeps(OIDN)
 
+  # OIDN is always built Release, including in a Debug bext tree.  On MSVC,
+  # oneTBB's headers otherwise auto-link tbb12.lib even when the imported
+  # TBB::tbb target correctly resolves to the tree's tbb12_debug.lib.  Rely on
+  # the explicit CMake target, as OIDN's fallback FindTBB module does.
+  set(OIDN_CXX_FLAGS_ARGS)
+  if (MSVC)
+    list(APPEND OIDN_CXX_FLAGS_ARGS
+      -DCMAKE_CXX_FLAGS:STRING=/D__TBB_NO_IMPLICIT_LINKAGE=1
+      )
+  endif (MSVC)
+
   ExternalProject_Add(OIDN_BLD
     URL "${CMAKE_CURRENT_SOURCE_DIR}/oidn"
     BUILD_ALWAYS ${EXT_BUILD_ALWAYS} ${LOG_OPTS}
@@ -15,6 +26,7 @@ if (ENABLE_OIDN)
     # OIDN's debug builds are broken upstream, so it is always built Release -
     # this matches OSPRay's own superbuild recipe (dep_oidn.cmake).
     -DCMAKE_BUILD_TYPE=Release
+    ${OIDN_CXX_FLAGS_ARGS}
     -DCMAKE_PREFIX_PATH=${CMAKE_BUNDLE_INSTALL_PREFIX}
     $<$<BOOL:${ONETBB_TARGET}>:-DTBB_ROOT=${CMAKE_BUNDLE_INSTALL_PREFIX}>
     $<$<BOOL:${ISPC_TARGET}>:-DISPC_EXECUTABLE=${CMAKE_BUNDLE_INSTALL_PREFIX}/${BIN_DIR}/ispc${CMAKE_EXECUTABLE_SUFFIX}>
@@ -41,6 +53,8 @@ if (ENABLE_OIDN)
     STEP_TARGETS install
     )
 
+  unset(OIDN_CXX_FLAGS_ARGS)
+
   TargetInstallDeps(OIDN OIDN_DEPENDS)
   # ISPC is only produced when a renderer group (e.g. OSPRAY) is active, so wire
   # the ordering dependency explicitly the same way embree does.

qt/qt_config.cmake.in

@@ -26,6 +26,14 @@ endif (NOT WIN32)
 # https://doc.qt.io/qt-6/configure-options.html
 set(CONFIG_EXTRA_OPTS ${CONFIG_EXTRA_OPTS} -qt-zlib -qt-libpng)
 
+# Qt's configure wrapper performs a nested CMake configure.  Preserve the
+# toolchain selected for bext instead of allowing another compiler on PATH to
+# produce an ABI-incompatible Qt build.
+list(APPEND QT_CMAKE_OPTS
+  "-DCMAKE_C_COMPILER=@CMAKE_C_COMPILER@"
+  "-DCMAKE_CXX_COMPILER=@CMAKE_CXX_COMPILER@"
+)
+
 if (QT_XMIN_ENABLED)
   list(APPEND CONFIG_EXTRA_OPTS
     -qpa xcb

strclear/CMakeLists.txt

@@ -20,11 +20,15 @@ if (ENABLE_STRCLEAR)
 
   RegisterDeps(STRCLEAR)
 
+  # strclear is a host-side build utility that scans multi-gigabyte library
+  # trees.  It has no ABI relationship with BRL-CAD, and an MSVC Debug build
+  # is prohibitively slow because checked iterators run inside its search
+  # loops.  Always optimize this helper, including in a Debug bext tree.
   ExternalProject_Add(STRCLEAR_BLD
     URL "${CMAKE_CURRENT_SOURCE_DIR}/strclear"
     BUILD_ALWAYS ${EXT_BUILD_ALWAYS} ${LOG_OPTS}
     CMAKE_ARGS
-    ${BUILD_TYPE_SPECIFIER}
+    -DCMAKE_BUILD_TYPE=Release
     -DBIN_DIR=${BIN_DIR}
     -DLIB_DIR=${LIB_DIR}
     -DDATA_DIR=${DATA_DIR}